The present invention relates to a method of spacing and turning over two coaxial cigarette lengths on a filter assembling machine.
Cigarette manufacturing machines are known to produce a continuous cigarette rod which, before being fed on to a filter assembling machine, is cut crosswise, usually not too neatly, into double cigarette lengths, i.e. lengths twice as long as the tobacco-filled part of a filter cigarette.
The said double lengths are then usually fed into respective recesses or slots on a splined roller at the input of a filter assembling machine, on which roller they are fed towards a cutting station where a disc cutter cuts the double lengths extremely accurately in half. The effect of this operation is to produce, inside each slot on the said input roller, two coaxial cigarette lengths essentially contacting each other over perfectly smooth end surfaces.
According to one known method of manufacturing filter cigarettes, the said two cigarette lengths are spaced apart in such a manner as to accommodate a double filter inbetween, i.e. a length of filter twice as long as that of a single cigarette. The said double filter is then banded to both the said cigarette lengths and the double cigarette so formed cut halfway along the double filter, so as to produce two single filter cigarettes.
One drawback on cigarettes produced this way is that the free end opposite the filter, though generally flat, is not always cut neatly, owing to its being produced by a propeller-type knife cutting the continuous cigarette rod crosswise as it comes off the said manufacturing machine.
On a known filter assembling machine, this drawback has been overcome by offsetting the said two cigarette lengths by means of rolling, moving one of the two lengths axially over to the opposite side of the other and then re-aligning the two lengths, usually by means of a second rolling operation, before inserting the said double filter.
By so doing, the perfectly smooth end faces on the two cigarette lengths are shifted outwards and the rough-cut ends inward facing each other. The latter are then connected to the opposite ends of the double filter, so as to produce essentially perfect finished cigarettes.
One drawback of the abovementioned method is that relative displacement of the two cigarette lengths for positioning the perfectly smooth end face outward involves two rolling operations and relatively long axial displacement of one cigarette length in relation to the other. Such operations usually result in tobacco leakage and invariably weaken the cigarette structure, in addition to impairing the resistance of the cigarettes to subsequent handling during packing.